The present invention relates to a disk drive apparatus that performs reproducing or reproducing/recording of information by rotating a circular plate-like disk which is a recording medium, and relates in particular to a loading mechanism for CD-ROM, DVD-ROM, DVD-RAM, etc.
A disk loading mechanism that performs operations that transport the disk constituting the recording medium into or out of the apparatus, and after transporting the disk into the apparatus, performs an operation that positions the reproduce/record head, which reproduces information on the disk or records information, in the prescribed state, is an extremely important mechanical element in a disk drive apparatus. This loading mechanism may have a configuration whereby the driving force is transmitted by means of a combination of a plurality of gears or rubber rings, as described in JP-A-10-283704.
The disk loading mechanism of a disk drive apparatus is required to perform operations that transport the disk into or out of the apparatus; and, when the disk is transported into the apparatus, an operation that raises and lowers the unit mechanism movable entity comprising an optical head, spindle motor, unit mechanism chassis, and unit holder, vertically within the apparatus, in order to fix the disk to the spindle motor; or, when the disk is transported out of the apparatus, an operation that raises and lowers the unit mechanism vertically within the apparatus is required, in order to detach the disk from the spindle motor. Also, for reasons of cost reduction, these operations are performed by a single rotary drive motor. Therefore, a plurality of gear conversions are used as the driving force transmission mechanism for performing each operation, and the configuration is extremely complex. Further, when the driving force is transmitted by means of a wheel gear or worm gear fixed to the rotating shaft of the rotary drive motor, and another wheel gear or a rack, contact noise is generated by the backlash which always exists in the meshing parts of the gears. In addition, as the above described rotating shaft of the rotary drive motor is placed in a cantilever state, whirling occurs at the tip of the shaft. As a result of this whirling of the shaft, the contact noise between gears due to backlash increases further.
The present invention is intended to solve these kinds of problems, and its objects is to design a reduction of the contact noise generated in the disk loading mechanism that performs transmission of a driving force by means of a rotary drive motor and a plurality of gears and a rack, between the above described gears and rack when the disk is transported into the apparatus, and provide a high-grade disk drive apparatus.
In order to solve the above described problems, one rotary drive motor is used in the disk loading mechanism, a worm gear is attached to the rotating shaft of this motor, and a disk loading operation is performed via another gear meshing with the above described worm gear, a mechanism that controls shaft whirling is provided on the rotating shaft, a first wheel gear and a second wheel gear are provided at two upper and lower levels, and a disk loading mechanism is used that performs disk tray inward-transportation operations by means of a rack provided on the disk tray via these gears, and operations to move up and down the movable entity comprising an optical head, spindle motor, unit mechanism chassis, and unit holder, that performs reproducing of information on the disk, or recording and reproducing, via a slide plate from the above described worm gear, by centrally rotating a rotary shaft provided on the above described unit holder.
A disk loading mechanism is provided wherein the helix angle of the above described worm gear is in a range from 50 degrees to 80 degrees.
Further, the shape of the above described supporting portion (bearing) provided on the structure that supports the tip of the worm gear attached to the above described rotary drive motor shaft is a V-shaped groove or conical groove with respect to the above described gear rotation center.